AMD released their Opteron 64-bit CPUs last year, and Microsoft is getting ready to release a 64-bit version of Windows Server 2003 that will run on them.

AMD released their Opteron 64-bit CPUs last year, and Microsoft is getting ready to release a 64-bit version of Windows Server 2003 that will run on them. A lot of people are wondering how these upcoming 64-bit environments will affect Citrix and Terminal Services.

Simply moving to a 64-bit platform will not necessarily increase performance over today’s 32-bit systems. However, there’s one key reason that I’m particularly excited about 64-bit Windows: The 32-bit Windows 2GB kernel memory limit. Terminal Server or Citrix systems running on 64-bit operating systems will not hit the same kernel memory limits that 32-bit versions run into today.

Let’s take a look at the 64-bit offerings that are (or soon will be) available.

First, we should mention that a 64-bit version of Windows Server 2003 has been available in a final and stable form for a year now. However, today’s 64-bit Windows only works on Intel’s Intanium2 CPUs. Unfortunately, the use of Itanium never caught on in Windows environments. Even today’s Itanium clock speeds top out at only 1.5GHz and their costs are astronomical. (A 1.4GHz Itanium2 CPU is $1400.)

People have pointed to Itanium and said that 64-bit Windows computing is far, far away, but the truth is that the Itanium was just a bad design that cost too much. Even Intel has essentially admitted this, and they’re dumping the entire Itanium line and copying AMD’s 64-bit CPU architecture.

Understanding the 64-bit AMD Opteron Processor

While Intel and HP were throwing marketing money at the Itanium, AMD was quietly developing its own 64-bit processor architecture from scratch. Codenamed “Hammer,” this architecture is the foundation for both the AMD Opteron and AMD Athlon64 processors. (Opteron and Althon64 are more-or-less the same thing, with Opteron being the server version and Althon64 being the desktop version.)

The most unique aspect of this architecture is that it allows CPUs to act as hybrid/convertible between 32- and 64-bit environments. These CPUs have three modes of operation:

Legacy 32-bit mode

64-bit mode running 32-bit applications

Full 64-bit mode, running a 64-bit OS with 64-bit applications

In the legacy 32-bit mode, you can use an Opteron system just like any other x86 32-bit system from Intel. You can install Windows 2000 or DOS or Windows 98 or the regular 32-bit Windows Server 2003 or pretty much whatever you want on an Opteron system. The system will behave like any standard Intel x86 32-bit system.

In fact, when comparing Intel Pentium 4 Xeon systems with AMD Opteron systems running 32-bit operating systems, the Opteron systems tend to offer better performance. This has absolutely nothing to do with the fact that it’s a 64-bit chip (since it’s running in 32-bit mode anyway.) Instead, AMD increased 32-bit performance by integrating the memory controller onto the chip itself and adding some new CPU registers.

When you’re ready to move up to a 64-bit operating system, you can do so with the same Opteron system you previously had a 32-bit OS running on. At this time, the 64-bit version Microsoft Windows Server 2003 for AMD chips is in beta, and it will be released when Microsoft releases Service Pack 1 for Windows Server 2003. (The new 64-bit version of Windows 2003 for AMD Opteron will have SP1 built in.)

64-bit Opteron systems cost about the same as 32-bit Intel P4 Xeon systems, and you can buy them from IBM and HP. I personally built a complete Opteron system for testing for under $1000.

From a software standpoint, there is no price difference between the 32- and 64-bit versions of Windows Server 2003, although the bigger hardware available means that most people who use 64-bit Windows Server will be require the Enterprise or Datacenter editions of Windows.

Once you have your 64-bit Opteron system up and running you’ll be able to install 32- or 64-bit applications.

64-bit Terminal Services

The 64-bit version of Windows Server 2003 looks and feels exactly like the 32-bit version. Terminal Server works fine in 64-bit. In fact, users can even move back and forth between 32- and 64-bit Terminal Servers without any problems. Logon scripts, GPOs, profiles, and printing all work the same in 32- and 64-bit Windows.

Since there aren’t really any 64-bit desktop applications available today, 64-bit Terminal Servers are going to end up running 32-bit applications.

This leads to an interesting design decision. With an AMD Opteron system, will you get better performance by installing 32-bit Windows with 32-bit applications or 64-bit Windows with 32-bit applications? (After all, this is the first time that we actually have a choice as to which version of the OS we can install on a specific system.) AMD claims that the 64-bit OS will yield better performance even with 32-bit applications, although I haven’t yet personally tested this head-to-head.

64-bit Citrix MetaFrame?

The only downside to running a 64-bit version of Windows is that some 32-bit applications (especially system-level applications) will simply not work. Citrix MetaFrame is one of those applications. Today’s version of Citrix MetaFrame Presentation Server simply will not install on a Terminal Server running the 64-bit version of Microsoft Windows Server 2003.

I would imagine that it would also be “hit or miss” with the third-party server-based computing applications, such as performance management and printing solutions.

So when will Citrix release a 64-bit version of MetaFrame Presentation Server? No one knows. When asked, Citrix officials have said that they build all their products based on market demand. When people start using 64-bit Terminal Servers in force, I’m sure we’ll see a 64-bit version of MetaFrame.

The Chicken or the Egg

Microsoft is certainly doing their part to push people towards 64-bit computing in the Longhorn timeframe, and we’ll certainly see a 64-bit version of MetaFrame Presentation Server at some point. For now, it looks like 64-bit Terminal Servers will shine in “Terminal Server only” environments (where it will be a no-brainer for larger implementations).

I still have my Opteron server, and I’ll continue to do more testing over the next few months.

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This message was originally posted by an anonymous visitor on May 26, 2004 The author's PC mentality is showing in complaints about the clock speed and price of Itanium processors. Multimillion dollar Superdomes and Altix 3000s aren't bought to run Far Cry and MySQL. And a 1.5 GHz Itanium beats a 2.2 GHz Opteron in TpmC and SAP-SD by 20% or more.

This message was originally posted by Brian Madden on May 26, 2004 I agree that Itanium2 is great for Superdome and scientific computing, but in this article I was talking about this stuff in the context of Microsoft Windows applications. Business applications do not make use of the Itanium's great FP capabilities, so that's why I think that the Citrix folks should be excited about Opteron. The SPECInt2000 benchmark of an Opteron 150 (like a 148 but 200MHz faster, bringing it to 2.4GHz) is 1566, while the Itanium2 at 1.5GHz has a SPECint2000 benchmark of 1408.

This message was originally posted by an anonymous visitor on May 27, 2004 I've got four Opteron boxes (246's) running 32-bit W2K3 and MPS3. There is a performance increase, but nothing like the differences I was seeing between he 32-bit vs. the 64-bit OS with just Terminal Services (I had a beta copy of the 64-bit on it for evaluation) Memory bandwidth was *extremely* high with the 64-bit OS. Let's say a basic Xeon system has 2.5-3GBps of memory bandwidth (pretty average). With the 64-bit I was seeing 9.6GBps!

Sign me up for th 64-bit version of Metaframe, Citrix. Stick a tigijet and a bunch of memory in this thing and its going to be amazing to see the scale of user load in 64-bit.

This message was originally posted by Ben on October 20, 2004 The Hammer is not built (coded) from scratch, they have made it backwardly compatible with the 32-bit X86, and are cutting corners everwhere to try and reduce cost!

This message was originally posted by Architect on November 26, 2004 The AMD 64 chips blows the doors off on the Intel version and Intel is spreading alot of FUD not to get people to look at AMD 64. Do not buy the bull they are behind in performance and price and failing wildly. HP also makes it hard to get an Evaluation unit with AMD 64 as well and they spread FUD as well as they have alot invested in Intel 64. The killer application for AMD 64 today is Terminal Services and Citrix better get thier game together quickly I cannot believ they do not see the market opp.

HP also makes it hard to get an Evaluation unit with AMD 64 as well and they spread FUD as well as they have alot invested in Intel 64.

Au contraire! HP are bending over backwards to get AMD eval kit out to people who want to try out 64-bit Terminal Services. They recognise that particularly in the blade space, using AMD processors will save on power and cooling requirements.

This message was originally posted by an anonymous visitor on May 27, 2004 I've got four Opteron boxes (246's) running 32-bit W2K3 and MPS3. There is a performance increase, but nothing like the differences I was seeing between he 32-bit vs. the 64-bit OS with just Terminal Services (I had a beta copy of the 64-bit on it for evaluation) Memory bandwidth was *extremely* high with the 64-bit OS. Let's say a basic Xeon system has 2.5-3GBps of memory bandwidth (pretty average). With the 64-bit I was seeing 9.6GBps!

Sign me up for th 64-bit version of Metaframe, Citrix. Stick a tigijet and a bunch of memory in this thing and its going to be amazing to see the scale of user load in 64-bit.